Changing a font Color

Hi

I have a client that has sent me a PDF file of text some is in black but there is also a grey text, i've opened it in Corel Draw X8 but i can't seem to be able to change the gray to black any ideas what i am doing wrong, i have ungrouped the text and even 'break text apart' 

My Roland GX24 is not picking up the Grey cut lines so i cant complete my job

Thanks for any replies

Jacks